Managed pressure drilling (MPD) is a drilling method used to control the annular pressure throughout a wellbore. Specifically, the annular pressure is kept slightly above the pore pressure to prevent the influx of formation fluids into the wellbore, but it is maintained well below the fracture initiation pressure. This is generally performed by using a drilling fluid that is weighted to be statically underbalanced relative to pore pressure, and by using surface back pressure generated by choke restrictions, to maintain a dynamic overbalanced state. The annular pressure is controlled by the use of a rotating control device (RCD). The RCD comprises a sealing element which forms a seal that creates a closed loop in the drilling system. The RCD diverts flow to the chokes, which as just discussed, are the pressure regulators for the closed loop. The dynamic control of annular pressures enables drilling wells that might not otherwise be practical.
In MPD operations when inserting wireline or tubing, processes which may be referred to as wirelining or tripping respectively, the closed loop provided by the RCD may need to be broken. This process is referred to as taking the well out of MPD mode. In order to maintain a proper pressure in the wellbore, this also requires a complete circulation and replacement of the statically underbalanced drilling fluid for a drilling fluid weighted to be overbalanced relative to pore pressure. This process requires additional time and expense. Further, the transition out of MPD mode may expose the formation to pressure changes which may induce formation damage. These problems are repeated when the wirelining or tripping operations are completed and the well has to be transitioned back into MPD mode. Moreover, the wirelining or tripping operations must be performed slowly as the sealing element of the RCD is not lubricated and may be damaged by wireline or tubing if the wirelining or tripping operation is not done at a sufficiently slow speed.
The illustrated figures are only exemplary and are not intended to assert or imply any limitation with regard to the environment, architecture, design, or process in which different examples may be implemented.